Volume-Oriented Incentive Spirometry-Assisted Diaphragmatic Breathing Exercise for Functional Heartburn or Reflux Hypersensitivity

Effect of Volume-Oriented Incentive Spirometry-Assisted Diaphragmatic Breathing Exercise in Patients With Functional Heartburn or Reflux Hypersensitivity: A Pilot Randomized Controlled Trial

The goal of this pilot randomized controlled trial is to determine whether volume-oriented incentive spirometry-assisted diaphragmatic breathing exercise (VIS-assisted DBE) can improve reflux-related symptoms and health-related quality of life in adults with functional heartburn (FH) or reflux hypersensitivity (RH).

The main questions it aims to answer are:

Does VIS-assisted DBE reduce reflux-related symptoms compared with usual care? Does VIS-assisted DBE improve health-related quality of life compared with usual care? Researchers will compare VIS-assisted DBE plus usual care with usual care alone to determine whether the intervention provides additional benefits in symptom relief and quality of life.

Participants will:

Complete baseline clinical evaluations and symptom questionnaires. Be randomly assigned to either the VIS-assisted DBE group or the usual care group.

Receive either VIS-assisted diaphragmatic breathing exercises twice daily for 20 minutes over a 4-week period in addition to usual care, or usual care alone.

Complete follow-up assessments after the 4-week intervention, including symptom and quality-of-life questionnaires

Functional heartburn (FH) and reflux hypersensitivity (RH) are disorders of gut-brain interaction characterized by persistent reflux-related symptoms despite the absence of significant esophageal acid exposure or structural abnormalities. Although proton pump inhibitors are widely used for reflux-related disorders, many patients with FH and RH continue to experience persistent symptoms, resulting in reduced health-related quality of life. Current evidence suggests that altered esophageal sensory processing, autonomic nervous system dysfunction, and impaired gut-brain axis regulation contribute to symptom generation in these disorders.

Diaphragmatic breathing exercise has emerged as a promising non-pharmacological intervention that may improve diaphragmatic function, enhance vagal activity, and reduce reflux-related symptoms. Volume-oriented incentive spirometry (VIS) provides visual feedback during breathing training and may improve the consistency and effectiveness of diaphragmatic breathing. However, evidence regarding the therapeutic effects of VIS-assisted diaphragmatic breathing exercise in patients with FH or RH remains limited.

This prospective, parallel-group, pilot randomized controlled trial is designed to evaluate the clinical effectiveness of VIS-assisted diaphragmatic breathing exercise in adults with FH or RH. Participants will be randomly assigned to receive either VIS-assisted diaphragmatic breathing exercise in addition to usual care or usual care alone. The study will assess whether the intervention improves reflux-related symptoms and health-related quality of life compared with usual care.

The findings of this study are expected to provide preliminary evidence regarding the feasibility and potential clinical benefits of VIS-assisted diaphragmatic breathing exercise as an adjunctive non-pharmacological treatment for functional heartburn and reflux hypersensitivity, and to support the design of future larger randomized controlled trials.

• Inclusion Criteria:

  • Adults aged 20 to 100 years.
  • Diagnosis of functional heartburn (FH) or reflux hypersensitivity (RH) according to the Rome IV criteria.
  • Normal upper gastrointestinal endoscopy without evidence of erosive esophagitis, Barrett's esophagus, or hiatal hernia.
  • Normal esophageal motility on high-resolution manometry (HRM) according to the Chicago Classification Version 4.0.
  • Diagnosis of FH or RH confirmed by 24-hour multichannel intraluminal impedance-pH (MII-pH) monitoring according to the Rome IV criteria and Lyon Consensus 2.0.
  • Able and willing to perform diaphragmatic breathing exercises and comply with study procedures.
  • Able to provide written informed consent.

• Exclusion Criteria:

  • Pregnant or breastfeeding women.
  • Severe cardiopulmonary dysfunction or chronic respiratory disease.
  • Inability to perform diaphragmatic breathing exercises or comply with the study protocol and scheduled follow-up visits